Technical Field
The present disclosure relates to a light emitting device and a plant cultivation method.
Description of Related Art
With environmental changes due to climate change and other artificial disruptions, plant factories are expected to increase production efficiency of vegetables and be capable of adjusting production in order to make it possible to stably supply vegetables. Plant factories that are capable of artificial management can stably supply clean and safe vegetables to markets, and therefore are expected to be the next-generation industries.
Plant factories that are completely isolated from external environment make it possible to artificially control and collect various data such as growth method, growth rate data, yield data, depending on classification of plants. Based on those data, plant factories are able to plan production according to the balance between supply and demand in markets, and supply plants such as vegetables without depending on surrounding conditions such as climatic environment. Particularly, an increase in food production is indispensable with world population growth. If plants can be systematically produced without the influence by surrounding conditions such as climatic environment, vegetables produced in plant factories can be stably supplied within a country, and additionally can be exported abroad as viable products.
In general, vegetables that are grown outdoors get sunlight, grow while conducting photosynthesis, and are gathered. On the other hand, vegetables that are grown in plant factories are required to be harvested in a short period of time, or are required to grow in larger than normal sizes even in an ordinary growth period.
In plant factories, the light source used in place of sunlight affect a growth period, growth of plants. LED lighting is being used in place of conventional fluorescent lamps, from a standpoint of power consumption reduction.
For example, Japanese Unexamined Patent Publication No. 2009-125007 discloses a plant growth method. In this method, the plants is irradiated with light emitted from a first LED light emitting element and/or a second LED light emitting element at predetermined timings using a lighting apparatus including the first LED light emitting element emitting light having a wavelength region of 625 to 690 nm and the second LED light emitting element emitting light having a wavelength region of 420 to 490 nm in order to emit lights having sufficient intensities and different wavelengths from each other.